In general, an over-the-range microwave oven refers to a microwave oven equipped with a venting system for exhauting heat, air and/or fumes during cooking. An over-the-range microwave oven is usually mounted above a gas or electric range. An air discharge unit is typically included in an air discharge duct and air flow of about 400 CFM can be achieved.
It is desirable to improve air discharge efficiency (or the ventilation efficiency) of an over-the-range oven. However, many issues tend to arise from efforts to improve the air discharge units, such as turbulent flows formed in the air discharge unit, increased noise level, and increased power consumption. These issues unfortunately counteract the efficiency of the oven,